The clinical manufacture of gene-modified T cells is currently a complex process that generally starts with obtaining the patient's peripheral blood mononuclear cells (PBMC). Current protocols feature a leukapheresis step, trading off an initially more cumbersome process (as opposed to a smaller volume blood draw) for an increased cell yield. PBMC are often enriched for T cells and activated prior to gene modification with viral or nonviral vectors. The modified T cells are then expanded in order to reach the cell numbers required for treatment, after which the cells are finally formulated and/or cryopreserved prior to reinfusion. The cell product must be subjected to a number of quality control assays and has to meet all release criteria and Good Manufacturing Practices (GMP) guidelines. Thus far, adoptive cell transfer (ACT) using gene-modified T cells has mainly been carried out by investigators who have developed their manufacturing process for small scale clinical trials by using the devices and infrastructure at hand. Such individualized therapies are complex: the cell manufacturing process is labor intensive, as it comprises many (open) handling steps (e.g., density gradient cell processing, gene modification, washing, feeding and so on) that require interventions from committed skilled operators who have undergone extensive training. The failure rate can be high owing to the high skill and time demands on clean room personnel to make these complex products. Moreover, dedicated infrastructure with clean rooms and all required instruments must be in place, qualified and functional to ensure aseptic and sterile containment. These requirements restrict such clinical manufacturing to a limited number of institutions worldwide. This in turn confines the number of runs and therefore the number of patients that can be served at any given time. Such unfavorable commercial distribution models impede investment and therefore the broad development of these promising therapies for the patients that need them (Kaiser A D, Cancer Gene Therapy (2015), 1-7).
Therefore, there is a need in the art for a method of generating gene-modified T cells for clinical use which is more robust and independent from the skills of the operators.